woman made ill from black mold
Brittany Hambleton
Brittany Hambleton
July 16, 2021 ·  6 min read

How Harmful Is Black Mold? One Woman’s Symptoms Highlight the Potential Dangers

Dana Anhalt, an artist from Huntington, New York, had been sick throughout her childhood and it only got worse. At 37, she was so impacted by whatever was ailing her that her ability to walk and use her hands was nearly lost. There were times when her weight dropped to just 70 pounds. Excruciating joint pain, along with symptoms that she says span four pages, affected nearly every system of her body. Doctors couldn’t figure out what was going on. Anhalt’s diagnoses spanned Common Variable Immunodeficiency (CVID) to Lyme disease to Mast Cell Activation Syndrome. But, in 2017 doctors figured out that Anhalt was being affected by her home environment—one that was infested with black mold [1].

As a result of several genetic defects, Anhalt’s body didn’t recognize the black mold and other chemicals in her home as foreign substances, which led to inflammation and pain.

What Is Black Mold?

According to the Centers for Disease Control and Prevention (CDC), black mold is a type of mold that can range from dark green to gray to black in color [2].

Officially called Stachybotrys chartarum (or sometimes Stachybotrys atra or Stachybotrys alternans), it can grow on most materials that have high cellulose and low nitrogen content—think wood, paper, dust, and lint.

Black mold happens when moisture is present from water damage. Water damage in a home could come from excessive humidity, a water leak, condensation, or flooding. There must be a continuous moisture present for its growth, and while it favors warm environments, it has the potential to grow anywhere.

This type of mold may have a slimy appearance and may have a musty or mildew smell. However, it’s important to remember that not all molds that look black are actually black mold.

The Prevalence of Black Mold

Black mold is less common than other types of mold, and it’s difficult to know exactly how common this mold is. In one study conducted in the United States, 6 percent of 1,717 buildings sampled contained black mold [3].

While this is a relatively small study, these numbers show that black mold is present in six out of every 100 buildings—or 1 out of every 16.7 homes (the buildings sampled were a mix of schools, hospitals, homes, and “other”).

Understanding Black Mold’s Toxicity

While certain molds produce what are called mycotoxins, molds themselves aren’t actually poisonous. It’s fairly rare that the presence of molds that release mycotoxins (also called toxigenic molds) cause severe health issues in humans, as they did in Dana Anhalt’s case [4].

Mold is natural and occurs pretty much everywhere and, in general, is not harmful to people. In fact, it plays a vital role in decomposing matter [5].

People are exposed to molds daily. However, if your home or work environment has had extensive water damage—whether or not you’re aware of it—you could be exposing yourself to higher levels of mold than normal, particularly if you spend a lot of time at these places or the building lacks proper air circulation (think basements, crawl spaces, and even cabinets).

Who’s at Risk to Be Affected By Black Mold?

While healthy people generally won’t be affected by a low level of mold in a building, people who have autoimmune diseases in addition to infants and other people whose immune systems aren’t up to par may be more likely to experience symptoms as a result of mold exposure [6].

To sum this up, while mold is common and is present in our daily lives, it’s a combination of the severity of mold in indoor spaces and the immunity of the individuals being exposed to the mold that can contribute to certain health problems.

How Black Mold Goes Unnoticed

Black mold may have a musty odor or be visually obvious in some homes, but for others, low (typically unharmful) levels of this mold won’t be easy to detect.

Many people have no reaction when exposed to mold, but some will have allergic reactions similar to those with pollen or animal allergies (except, when caused by mold, will typically not be seasonal but may be worse during the warmer seasons when mold thrives). People may have a rash, flu-like symptoms, or asthma.

If your home doesn’t have an odor but you’re having symptoms that a doctor has diagnosed as allergies or a cold but won’t go away even with treatment, it might be time to get yourself or your home evaluated for black mold.

Symptoms of Exposure to Black Mold

While Dana Anhalt had a range of excruciating symptoms as the result of her genetics and exposure to black mold, experiencing these harsh symptoms typically isn’t common.

Fever-like allergies are the most common symptoms, not severe health issues, although people with respiratory or immunological diseases can experience consequences such as lung infections.

Mold exposure has even been linked to depression in one study, although the results of this research and what they mean are not yet clear [7].

Other symptoms of black mold exposure taking its toll on your health may include:

  • Respiratory symptoms include a cough, wheeze, or asthma-like symptoms.
  • Headaches.
  • Allergy-like symptoms including sneezing, an itching or runny nose, congestion, dry skin or a rash [7].
  • Depending on your unique immunity, you may have other, more serious symptoms that can impact your overall health.

Your doctor may want to conduct an allergy test (a skin prick test) for mold or advise you to get your home or workplace evaluated for mold. Other diagnostic tests include a blood test, which can measure the number of mold antibodies in your system [8].

You Can Prevent Black Mold in Your Home or Office

You should absolutely take preventative measures to keep black mold and other types of mold to a minimum in your home and office. There are many things you can do to reduce your exposure to mold and minimize it in your home [9].

  1. Keep humidity levels as low as possible: preferably below 50 percent, but below 35 is ideal (get a dehumidifier that will tell you the percentage!).
  2. Properly ventilate rooms that can have high humidity and moisture including kitchens, bathrooms, and laundry rooms with an exhaust fan.
  3. Remove standing water as soon as possible from your home and dry out damp carpets and furniture using a dehumidifier or wet vac (preferably both).
  4. Prevent water leaks indoors and ensure proper water drainage around your home from gutters to prevent mold in basements from affecting your indoor air quality.
  5. Use filters in your central air conditioning and change them as recommended. Filters that are designed for people with asthma and allergies can help trap mold spores.

Remember, while the Environmental Protection Agency (EPA) says it’s impossible to remove all mold and mold spores indoors, it’s still important to keep your mold exposure to a minimum, particularly if your immune system is deficient [10].

Be Aware of Your Risk!

As for Dana Anhalt, her team of doctors advised her to move out of her home and leave everything behind, including most of her possessions. They, like the EPA, must have known it would be impossible to remove all the mold spores from her items, and due to her severe symptoms, she would need to find a new place to live and throw away most of her things.

While most people won’t experience symptoms as Dana Anhalt did, being aware of your exposure to mold and taking preventative measures in your home or work environment may help prevent future health issues for you and your family!

Keep Reading: Here’s What Happens To Your Body When You Walk Every Day


  1. “New Yorker left BEDRIDDEN for almost a decade and sick all of her adult life after being poisoned by toxic mold in her apartment basement” The Daily Mail. March 12, 2017.
  2. Facts about Stachybotrys chartarum.” CDC
  3. Stachybotrys chartarum (or S. atra or S. alternans) [CAS No. 67892-26-6] NTP. June 2004.
  4. Mold.” NIH.
  5. Mold Resource Center.” AIHA
  6. Brown Study Finds Link Between Depression and Household Mold.” Brown University. August 29, 2007.
  7. Mold Allergy.” AAFA
  8. “Mold Allergy.” Mayo Clinic
  9. Mold 101: Effects on Human Health.” Poison.
  10. A Brief Guide to Mold, Moisture,and Your Home.EPA

Correction Notice (12/16/2021): This article originally stated that Dana Anhalt’s black mold diagnosis was recent, however, this occurred in 2017. This error has since been corrected. The Daily Mail Source was also added to source list.